export default {
  namespaced: true,
  state: () => ({
    cart: JSON.parse(uni.getStorageSync('cart') || '[]')
  }),
  mutations: {
    addToCart(state, goods) {
      const findResult = state.cart.find(x => x.goods_id === goods.goods_id);
      // 如果购物车里没有这个物品，直接添加
      if (!findResult) {
        state.cart.push(goods);
      } else {
        findResult.goods_count++;
      }
      this.commit('m_cart/saveToLocal');
    },
    // 将购物车数据存储到本地
    saveToLocal(state) {
      uni.setStorageSync('cart', JSON.stringify(state.cart));
    },
    // 更新 radio 状态
    updateRadioStatus(state, goods) {
      const findResult = state.cart.find(x => x.goods_id === goods.goods_id);
      if (findResult) {
        findResult.goods_state = goods.goods_state;
        this.commit('m_cart/saveToLocal');
      }
    },
    updateCartCount(state, goods) {
      const findResult = state.cart.find(x => x.goods_id === goods.goods_id);
      if (findResult) {
        findResult.goods_count = goods.goods_count;
        this.commit('m_cart/saveToLocal');
      }
    },
    removeGoodsById(state, goods_id) {
      // 调用数组的 filter 方法进行过滤
      state.cart = state.cart.filter(x => x.goods_id !== goods_id)
      // 持久化存储到本地
      this.commit('m_cart/saveToLocal')
    },
    updateAllGoodsChecked(state, newState) {
      // 更新购物车里的每一个数据
      state.cart.forEach(x => x.goods_state = newState);
      this.commit('m_cart/saveToLocal')
    },

  },
  getters: {
    total(state) {
      let c = 0;
      state.cart.forEach(goods => c += goods.goods_count);
      return c;
    },
    // 返回已选中的商品数量
    checkoutCount(state) {
      return state.cart.filter(x => x.goods_state).reduce((total, item) => total += item.goods_count, 0);
    },
    // 统计总价钱
    checkedGoodsAmount(state) {
      // 先使用 filter 方法，从购物车中过滤器已勾选的商品
      // 再使用 reduce 方法，将已勾选的商品数量 * 单价之后，进行累加
      // reduce() 的返回值就是已勾选的商品的总价
      // 最后调用 toFixed(2) 方法，保留两位小数
      return state.cart.filter(x => x.goods_state)
        .reduce((total, item) => total += item.goods_count * item.goods_price, 0)
        .toFixed(2)
    }
  }
}
